The Bell (Cedar Mountain) district is in the Cedar Mountain Range in eastern Mineral County near the Nye County border.
The silver-lead deposit at the Simon mine was discovered in 1879, but the gold deposits in this area were not found until later. Gold was discovered at the Copper Contact mine in 1902 and at the Olympic (or Omco) mine in 1915 (Vanderburg, 1937b, p.19).
Before 1919 the Olympic mine yielded $700,000 (about 32,000 ounces of gold) in ore that contained gold with a fineness of 500 (Knopf, 1921a, p. 381). Total gold production of the district through 1959 was about 34,000 ounces.
The gold deposits are associated with Tertiary volcanic rocksâ€”rhyolites and andesitesâ€”that underlie lake beds of the Esmeralda Formation (Knopf, 1921a, p. 377-380). At the Olympic mine, the vein is in the upper of two rhyolite flows that have a trachyte flow between them. The vein consists of white sugary quartz containing gold that is not readily visible and is faulted in several places. At the Golden Mile and Clay Peters mines, gold-bearing quartz veins occur in the Luning Formation of Triassic age (Ross, 1961, table 6.1).
Silver veins were discovered in the Candelaria district, which is 22 miles south of Mina in the Candelaria Mountains, in 1863 by a party of Spaniards. The town of Columbus was founded, but the district developed slowly because of the complex mineralogy of the oxidized ores. In the 1870's, the Northern Belle mine was successfully developed. The town of Candelaria was soon constructed near the mine, rail connections were made, and the district became one of the leading silver camps in the State. In 1884 the Northern Belle mine was involved in litigation and was sold. About this time the Mount Diablo mine became an important producer, and this mine and the Argentum (the consolidated Holmes and Northern Belle) kept the district booming until the bonanza ores were exhausted in the early 1890's (Knopf, 1923, p. 4-5). The camp declined until 1919, when a brief revival took place under the sponsorship of the Candelaria Mines Co. (Vanderburg, 1937b, p. 25). No important activity has been recorded since, although small-scale operations were reported as recently as 1955 (Page, 1959, p. 9).
The Candelaria has been a silver-producing district, and only relatively insignificant quantities of gold have been recovered. The early production data gave no figures on gold. Knopf (1923, p. 5) mentioned a minimum of $20 million worth of silver to about 1920. From 1903 through 1958, a total of 13,024 ounces of gold was produced.
The oldest rock unit of the district is the Palmetto Formation, composed of chert, dolomite, and shale of Ordovician age (Page, 1959, p. 15-44). This is unconformably overlain by sandstone of the Diablo Formation of Permian age. Overlying the Diablo is the Candelaria Formation, which is composed of sandstone, shale, and a few limestone beds and is of Early Triassic age. A large west-trending mass of serpentine containing fragments of Candelaria shale is exposed in the east-central part of the district. Numerous basic dikes, older than the serpentine and acidic dikes and younger than the serpentine, occur throughout the district. In the vicinity of the Northern Belle mine a rock is exposed which is a complex of sheared and brecciated metasedimentary rocks and metadolerite. All the foregoing rocks are unconformably overlain by Tertiary and Quaternary volcanic rocks, consisting of basalt, dacitic tuffs and flows, rhyolite, and andesitic breccia.
The pre-Tertiary rocks were complexly folded and faulted, perhaps during several episodes, before deposition of the Candelaria Formation. Folding on an east-west axis occurred during post-Triassic, pre-Tertiary time and was accompanied by shearing, faulting, intrusion of peridotite and dikes, and finally by deposition of metalliferous lodes. Additional faulting began in early Pleistocene time and culminated in the fault blocks which characterize the present physiography.
Several types of veins are found in the Candelaria district, but only one type is of economic importanceâ€”mineralized fault zones recognizable on the surface by limonite-stained outcrops of fault breccia. Primary ore consists mainly of pyrite and sphalerite and minor galena, chalcopyrite, and arsenopyrite in a gangue of altered country rock, quartz, and dolomite. Oxidized ore, most of which was mined in the early days, is composed predominantly of limonite and manganese oxide with small amounts of bindheimite, anglesite, smithsonite, and cerussite (Page, 1959, p. 47-58).
Page 2 of 4